One of many benefits to Moore's law is that the price of technology decreases over time. A particular market segment taking advantage of this benefit is the video market, including video surveillance.
Early uses of video surveillance included a human visually inspecting a display from a video camera, continuously watching for an unusual scene. Recordings were made and stored for later review, if the need arose. One problem in this usage model is that the person watching the display could fatigue as long periods of time would often pass with no change in the displayed scene. Later surveillance processes included automatic monitoring of video, either live or previously recorded, where a machine compared frames of a video display to previous frames, and signaled when a change occurred. Such a change could be a person walking within the scene being monitored, for example. Yet later processes include automatically tracking personnel entering and exiting the building, sometimes including face-recognition features to determine identity.
These automated systems are only as good as the quality of the underlying video signal, however. Many times surveillance is performed with low quality cameras, in an effort for maximum area coverage with a minimum of expense. All qualities of cameras, but especially lower quality cameras, are affected by ambient video conditions, such as variable light sources during different times of day. Additionally, other factors such as colored or flashing lights within the video can make it difficult for automatic analysis of the live or recorded video.
Embodiments of the invention address these and other limitations in the prior art.